While type 2 diabetes is considered a lifestyle-mediated chronic disease, the contribution of environmental factors to diabetes risk is increasingly recognized. Recently, geographic variation in the diabetes prevalence has been reported by CDC scientists with the identification of a ?Diabetes Belt? located in the southeastern US, where residents have a higher type 2 diabetes rate comparing to those live in other regions of the US. The similarity of this geographic variation across age, race, and sex, and the extreme magnitude of the differences between high- and low-prevalence areas suggest that the geographic pattern of diabetes rate cannot be explained by healthcare practices and/or socioeconomic status. Instead, environmental factors may be important determinants of the geographic variation in diabetes risk. Studies indicate that imbalanced homeostasis of certain minerals may damage anti-inflammatory and anti-oxidant defense as well as glucose tolerance, which together play pivotal roles in the pathogenesis of diabetes. In addition, studies have linked some heavy metal exposure to the risk of diabetes, though the underlying mechanisms are not completely clear. Despite this, a critical gap remains in the literature on how minerals affect diabetes development. In the proposed project, we will examine mineral status in relation to the incidence of diabetes and insulin resistance in an ancillary study of the REasons for Geographic And Racial Differences in Stroke (REGARDS) study ? an ongoing US national population-based cohort of 30,239 African American and Caucasian adults, aged 45 and older at baseline.